论文标题

几何顶点分解和联络图

Geometric vertex decomposition and liaison for toric ideals of graphs

论文作者

Cummings, Mike, Da Silva, Sergio, Rajchgot, Jenna, Van Tuyl, Adam

论文摘要

多项式理想的几何顶点可分解性是对简单复合物的顶点可分解性属性的理想理论概括。实际上,均质的几何顶点可分解理想是激进的和cohen-macaulay,并且位于完整交叉点(Glicci)的Gorenstein联络类中。在本文中,我们对有限的简单图$ g $的感谢您的理想$ i_g $进行了调查。我们首先展示了几何顶点的可分解性在张量产品下的表现,这使我们能够限制连接的图。然后,我们描述了保留几何顶点可分解性的图形操作,从而使我们能够构建许多图形,其相应的复曲率理想在几何顶点上是可分解的。利用君士坦丁库和戈拉的作品,我们证明了两分图的复曲面理想在几何顶点可以分解。我们还提出了一个猜想,即具有无方形变性的所有图形理想相对于词典阶,在几何顶点上都是可分解的。作为证据,我们证明了猜想的情况:$ i_g $的通用gröbner基础是一组二次二项式。我们还证明,其他一些图的家庭具有$ i_g $是Glicci的属性。

The geometric vertex decomposability property for polynomial ideals is an ideal-theoretic generalization of the vertex decomposability property for simplicial complexes. Indeed, a homogeneous geometrically vertex decomposable ideal is radical and Cohen-Macaulay, and is in the Gorenstein liaison class of a complete intersection (glicci). In this paper, we initiate an investigation into when the toric ideal $I_G$ of a finite simple graph $G$ is geometrically vertex decomposable. We first show how geometric vertex decomposability behaves under tensor products, which allows us to restrict to connected graphs. We then describe a graph operation that preserves geometric vertex decomposability, thus allowing us to build many graphs whose corresponding toric ideals are geometrically vertex decomposable. Using work of Constantinescu and Gorla, we prove that toric ideals of bipartite graphs are geometrically vertex decomposable. We also propose a conjecture that all toric ideals of graphs with a square-free degeneration with respect to a lexicographic order are geometrically vertex decomposable. As evidence, we prove the conjecture in the case that the universal Gröbner basis of $I_G$ is a set of quadratic binomials. We also prove that some other families of graphs have the property that $I_G$ is glicci.

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